LOL. If there were a way to dig a Grand Canyon deep moat around a good sized area in the outback . . . take all their deadly critters there and then send the evil doers there—might be worth considering. But there are a lot of nice Aussies there. Would hate to bump our plague onto them.
Import all the nice Aussies here and let Australia start over again like the prison colony it was.
Maybe in 200 years the derp convicts will have evolved into "nice Aussies" too.
Expand your thinking.
Bagster